1/4" x 20 Left Hand BSW Bottoming HSS Tap

About this item:

• 1/4" x 20 Left Hand BSW Bottoming HSS Tap
• HSS BSW LEFT HAND Bottoming Hand and Machine Tap.
• British Standard Whitworth has a thread angle of 55 degrees as opposed to 60 degrees in Metric and Unified threads.
• This thread form was developed by Sir Joseph Whitworth in 1841.
• The thread form has rounded roots and crests and is specified in BS84:1956.
• Bottoming Taps have a lead of two threads and are used to ensure minimum thread run-out when tapping to the bottom of a blind hole.
• Bottoming Taps are typically preceded by the use of a Taper or Intermediate Tap.
• Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use.